Over the past decade, a variety of optical switch technologies were developed by the photonic industry for telecommunication applications such as network protection, network restoration, equipment and device redundancy, performance monitoring, research and development, spectral interferometry, and the like. Other applications for optical switches include medical, aerospace, national defense, and other manufacturing and industrial industries. Despite the growing demand for optical switches, virtually none of technologies have been commercially exploited due to reliability, scalability, optical performance, cost, and long term performance problems associated with design tolerances required for manufacturing and assembling optical switches and optical switch containing devices.
A number of the foregoing applications for optical switches require switch assembly tolerances that are beyond the level of achievability for mass production of such switches. For example, for critical switching applications, optical switches must be optically clear so that the insertion loss is less than about 0.5 dB, the temperature dependence loss is less than 0.1 dB at −40° to +85° C., the polarization dependence loss must be less than 0.05 dB, the low wavelength dependent loss must range from 1250 to 1650 nanometers, and there must be a low wavelength dependent loss for multi-mode switching.
From an operational reliability point of view, the optical switches must maintain operability during long term dormancy and storage at temperatures cycling from −40° to +85° C., remain operable during extreme shock at vibration episodes, be capable of operation for tens of millions of switching cycles, have a resistance to humidity above about 85% relative humidity, have a repeatability within 0.01 dB over a life time which may include tens of millions of cycles, or one cycle after a prolonged dormant period of standby use. Other important characteristics of optical switches are that they have switching times of less than about 5 milliseconds, very low operating current, low voltage, and low power requirements, power-off latching, and multi-mode or single mode capabilities.
Many of the foregoing parameters are extremely difficult or impossible to achieve without a radical change in optical switch technology. In view of the foregoing, there is a continuing need for improved optical switches that can be mass produced at relatively low cost and in relatively high yields.
With regard to the foregoing, the disclosure provides an optical switch element, methods for manufacturing an optical switch element, and optical switch devices containing the optical switch element. The optical switch element includes, a housing containing a longitudinal channel therein having a channel axis defined along a length of the longitudinal channel. The longitudinal channel contains a first machined surface on a first side of the channel, a second surface on an opposite side of the channel from the first surface, a first magnetic coil adjacent the first surface of the channel and a second magnetic coil adjacent the second surface of the channel. An elongate shuttle having a mirrored surface on at least one end thereof is disposed in the longitudinal channel for lateral movement substantially transverse to the channel axis between a first latch position adjacent the first machined surface and a second latch position adjacent the second surface. The shuttle includes a rare earth magnet for interacting with the first and second magnetic coils to cause movement of the shuttle between the first latch position and the second latch position. At least one shuttle guide is provided for guiding movement of the shuttle between the first latch position and the second latch position.
In another embodiment, the disclosure provides a method for manufacturing an optical switch element for an optical switching. The method includes providing an elongate housing including a channel portion and a cover plate portion. An elongate channel is machined in the channel portion of the housing. The elongate channel has a channel axis defined along a length thereof and has a first machine surface and a second surface opposite the first surface. A first magnetic coil is included in the housing adjacent the first surface. A second magnetic coil is included in the housing adjacent the second surface. A planar surface is machined on the cover plate portion to provide a first latch surface. An elongate substantially rectangular shuttle containing a mirrored surface on at least one end is disposed in the elongate channel for lateral movement transverse to the channel axis. The shuttle contains a rare earth magnet for interacting with the first and second magnetic coils. At least one shuttle guide is installed in the housing for translational movement of the shuttle thereon. The cover plate portion is fixedly attached to the channel portion to provide the optical switch element.
An advantage of embodiments of the disclosure is that the body and shuttle components of an optical switch element are capable of manufacturing and assembly without the need for multiple six-axes alignment steps. In a conventional optical switch element, the shuttle is cylindrical and slides longitudinally along a longitudinal axis of an elongate, cylindrical channel in the switch element housing. Accordingly, in such a device, six axes are articulated in order to achieve low insertion loss, with virtually no excess loss due to misalignment along any of the six axes.
In the switch elements of the disclosed embodiments, the shuttle moves in a single Y or X-axis orthogonal to a Z-axis, to a latch position on a machined, substantially planar surface of the housing channel. One or more guides are provided for translational movement of the shuttle thereon along the X-axis and for alignment of the shuttle along the Z-axis. The pitch, roll, and yaw of the device are permanently fixed by mating a machined, substantially planar surface of the shuttle with a machined, substantially planar surface of the housing channel.